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At least 19 recordsLinked to original sources

PubMed1986

Monoclonal antibodies against human leucocyte antigens. I. Antibodies against beta-2-microglobulin, immunoglobulin kappa light chains, HLA-DR-like antigens, T8 antigen, T1 antigen, a monocyte antigen, and a pan-leucocyte antigen.

Monoclonal antibodies against several human leucocyte cell surface antigens were prepared and characterized: B2M-02, a non-cytotoxic antibody against beta-2-microglobulin; MEM-09 and MEM-40, against immunoglobulin kappa-type light chains; MEM-12, MEM-24G and MEM-32B, all against a monomorphic determinant in MHC class II antigens, presumably HLA-DR, dependent on the association of alpha and beta chains; MEM-15 and MEM-18, against a monocyte antigen of 55 kDa; MEM-28, against a 200 kDa antigen expressed on all leucocytes; MEM-31, against the T8 antigen of the cytotoxic/suppressor T-lymphocyte subpopulation; MEM-32, against the T1 antigen of T lymphocytes.

Animals↗

PubMed1990

The relationship between antigen concentration, antigen internalization, and antigenic complexes: modeling insights into antigen processing and presentation.

Native antigen is processed and subsequently presented on the surface of antigen-presenting cells, an important step in the elicitation of an immune response. The early events of antigen processing and presentation include: ingestion of a native antigen, intracellular degradation to expose an antigenic peptide fragment, binding of this fragment with an MHC class II molecule, and display of this newly formed complex on the cell surface. Through the development of a mathematical model, a set of mathematical equations which describes the time-dependent appearance, disappearance, and movement of individual molecules, quantitative insight can be gained into the pathways and rate-limiting steps of antigen presentation. The credibility of the model has been verified by comparison to literature data. For example, it has been shown experimentally that macrophages require 60 min for effective antigen presentation, whereas B cells require 6-8 h. The mathematical model predicts these presentation times and identifies the difference in the cell's respective pinocytic rates and sizes as important parameters. B cells capture antigen in their environment through nonspecific fluid-phase pinocytosis as well as by binding antigen to their surface immunoglobulin, allowing receptor-mediated uptake. Uptake of antigen via receptor-mediated endocytosis has been reported to require 1,000-fold less antigen than uptake via nonspecific pinocytosis. The mathematical model clearly predicts this decrease in concentration. The model also makes quantitative predictions for the number of MHC class II-antigen complexes needed to produce T cell stimulation.

Animals↗

PubMed1987

Antigenic heterogeneity of carcinoembryonic antigen in the circulation defined by monoclonal antibodies against the carbohydrate moiety of carcinoembryonic antigen and closely related antigens.

Six mouse monoclonal antibodies reactive with carcinoembryonic antigen (CEA) were prepared and used for the analysis of the antigenic heterogeneity of CEA in patient sera. Their reaction specificity and the chemical nature of antigenic epitopes recognized by them were analyzed by radioimmunoassay on the basis of reactivities with different preparations of CEA, normal fecal antigen 2, and nonspecific cross-reacting antigen 2 before and after chemical and/or enzymatic treatment. Two antibodies, F3-30 and F4-82, raised with CEA were reactive with different peptide epitopes on the antigen molecules and revealed a quite universal reactivity with all CEA, normal fecal antigen 2, or nonspecific cross-reacting antigen 2 preparations tested. The serum CEA values obtained with these antibodies were highly correlated with those obtained with conventional radioimmunoassays for CEA. The other four antibodies (F4-11 and F33-37 raised with CEA, F8-52 with normal fecal antigen 2, and F48-60 with nonspecific cross-reacting antigen 2) were found to recognize carbohydrate epitopes with different specificities and revealed very heterogeneous reactivities. The serum CEA values estimated with these four antibodies were highly variable depending on the antibody used, suggesting that the expression of carbohydrate epitopes on the CEA molecules in patient sera was quite heterogeneous. The antigenic heterogeneity of the carbohydrate epitopes was detected even in a single patient serum by affinity chromatography. The causes that give rise to the difference in CEA values between the Roche and the Daiichi kits were analyzed on the basis of reactivities of three groups of patient sera, which showed extremely different ratios for the Roche and Daiichi kits, with monoclonal anti-carbohydrate antibodies. The results obtained suggest that, at least in part, the diversity of antigenic expression on carbohydrate chains on the CEA molecules in patient sera and the variation in specificity or quantity of anti-carbohydrate antibodies in the polyclonal antibody preparations used for the respective assay systems may result in the differences in the estimated CEA values.

Antibodies, Monoclonal↗

PubMed1996

[Molecular biology of Lewis antigens--histo-blood type antigens and sialyl Lewis antigens as tumor associated antigens].

The biosynthetic pathways of the Lewis histo-blood type antigens, Lewis a (Le(a)) and Lewis b (Le(b)), in correlation with ABH antigen synthesis and the synthesis of sialyl Lewis antigens, sialyl Lewis a (sLe(a)) and sialy Lewis x (sLe(x)), known as tumor associated antigens are described based on the recent molecular biological studies. Individuals are divided by their erythrocyte Lewis antigen phenotypes into three types, Le (a+b-) which has Le(a) antigen but not Le(b) antigen, Le (a-b+) which has Leb but not Le(a), and Le (a-b-) having neither Le(a) nor Leb. It was verified that Le (a-b-) individuals are the homozygotes with the nonfunctional Lewis gene (Le gene) which is inactivated by the missense mutations. Two kinds of the inactivated Le gene alleles were found in the Japanese population, and named le1 and le2. Individuals having a Le (a+b-) or a Le (a-b-) -non-secretor phenotype are the mutants who lack the secretor enzyme (Se enzyme) activity. The Se gene encoding the Se enzyme has been recently cloned and analyzed for the mutation resulting in inactivation of the Se enzyme of the non-secretor individuals. Our Se gene mutant analyses on the Japanese population ensured that the Se gene is responsible for synthesis of the Le(b) antigen. Mutant analyses of the other genes, H gene and FucTVI gene, which are also involved in the synthesis of Lewis antigens are described. We recently demonstrated that the sLe(a) antigen is the product of the Lewis gene since all le/le patients, who are determined as the genuine Lewis negative individuals by Le genotyping, did not express any kinds of type 1 chain Lewis antigens (Le(a), Le(b), and sLe(a)) in their digestive organs. It is, therefore, unuseful to measure the CA19-9 titer of the genuine Lewis negative cancer patients.

Genotype↗

PubMed1997

Selective elimination of antigen-specific line T cells and ex vivo antigen-primed lymph node cells by antigen-targeted drug-labeled antigen-presenting cell membranes.

Since antigen-specific autoaggressive T cells have been found in association with many autoimmune diseases, a treatment to eliminate such antigen-specific T cell clones was developed. The complex of peptide antigen and class II MHC protein is used to target a cytotoxic drug to antigen-specific T cells. The drug is bound covalently to antigen-presenting cells (APC) and protein antigens (Ag) are added to the cells for processing and presentation of peptides. The APC contain class II MHC (Ia) protein to present the peptide Ag to the T cell receptor and adhesion proteins for optimal interaction with the T cell. Either the Ag-bearing intact APC or Ia+ membranes shed or released spontaneously from them were used as drug carriers to target the drug to the T cells. The drugs being used are phototoxic compounds. When irradiated with light of an appropriate wavelength, they give off toxic free radicals and singlet oxygen. These toxic by-products are short-lived and damage cells only in their immediate vicinity, cutting down on nonspecific side effects. APC from thymus cells, or their shed membranes bearing Ia-Ag peptide complexes, were able to target the phototoxic drug specifically to Ag-specific T line cells and ex vivo Ag-specific lymph node cells. Proliferation of the target T cells was inhibited at a three to four times lower drug concentration than required to affect control T cells. The Ag-specific effect was inhibited by anti-Ia antibody and by drug-free membranes carrying the Ag-Ia complex. This indicated that the antigen-specific phototoxic effect was mediated by interaction of the Ag-Ia complex with the T cell receptor.

Adjuvants, Immunologic↗

PubMed2002

Complexed prostate-specific antigen, complexed prostate-specific antigen density of total and transition zone, complexed/total prostate-specific antigen ratio, free-to-total prostate-specific antigen ratio, density of total and transition zone prostate-specific antigen: results of the prospective multicenter European trial.

This prospective, multicenter European Prostate Cancer Detection study evaluated the value and performance of the molecular forms of prostate-specific antigen (PSA) and their derivatives in combination with prostate gland and transition zone volumes in early detection of prostate cancer in patients with PSA levels between 4 and 10 ng/mL. Of 750 men enrolled at 7 different European urology centers into the study between November 2001 and March 2002, 340 (45.3%) had a total PSA (tPSA) between 4 and 10 ng/mL (age range, 46 to 87 years). In all patients, the ratio of complexed PSA (cPSA) to tPSA (c/tPSA), cPSA density (cPSAD), cPSAD of the transition zone, PSA, free PSA (fPSA), ratio of fPSA to tPSA (f/tPSA), tPSA density (PSAD), and PSAD of the transition zone were measured and collected 5 to 10 minutes before the sextant biopsy with 2 additional transition zone cores. Measurements of tPSA and fPSA were done with the AxSYM test, whereas cPSA was measured with the ACS 180 cPSA assay. All patients had a transrectal ultrasound-guided sextant prostate biopsy, and 2 additional transition zone biopsies and total and transition zone volumes were measured at the time of biopsy. Histopathologic findings revealed benign histology in 237 patients and prostate cancer in 103 patients (69.7% and 30.3%, respectively). Statistically significant differences included larger total volumes, larger transition zone volumes, and f/tPSA in patients with benign disease (P = 0.0009, P <0.0001, P <0.0001, respectively). At 90% and 95% sensitivity, specificity of cPSA was significantly greater than that for PSA (P <0.0001). At sensitivity levels of 90% and 95%, the specificity of the cPSA assay using cutoff values of 3.06 and 2.52 ng/mL was 20.3% and 9.1%, respectively. A cPSA cutoff value of 6.95 ng/mL and 7.57 ng/mL afforded 90% and 95% specificity for detecting prostate cancer. The area under the curve (AUC) in the receiver operating characteristics curve of cPSA was statistically significantly higher compared with tPSA (60.8 vs 56.9, P = 0.032). AUC for volume-related parameters PSAD, cPSAD, PSAD of the transition zone, and cPSAD of the transition zone were 62.8%, 63.1%, 63.0%, and 63.6%, respectively. cPSA performs better than tPSA in the differentiation between benign disease and prostate cancer and provides similar information to the f/tPSA ratio. In addition, cPSA and cPSA volume-related parameters (cPSAD, cPSAD of the transition zone) further improved the specificity of PSA in early detection of prostate cancer.

Aged↗

PubMed1995

Sensitivity of monoclonal antibodies to carcinoembryonic antigen, tissue polypeptide antigen, alpha-fetoprotein, carbohydrate antigen 50, and carbohydrate antigen 19-9 in the diagnosis of colorectal adenocarcinoma.

PURPOSE: This study was designed to establish the sensitivity of monoclonal antibodies to carcinoembryonic antigen (CEA), alpha-fetoprotein (AFP), tissue polypeptide antigen (TPA), carbohydrate antigen 50 (CA 50), and carbohydrate antigen 19-9 (CA 19-9) and the efficacy of the joint determination of several tumor markers, as well as the dynamics of postoperative normalization of each marker in the absence of recurrence. MATERIALS AND METHODS: A prospective study was carried out in 100 patients subjected to surgical resection of colon adenocarcinoma. Serum concentrations of these markers were determined the day before surgery and seven days, two months, and six months after surgery. RESULTS: The results demonstrate that sensitivity increased as the disease spread and that CA 19-9 was the most sensitive tumor marker. The rate of false negatives was 40 percent for Dukes Stage A lesions, 19 percent for Dukes Stage B, 7 percent for Dukes Stage C, and 0 percent for Dukes Stage D. Determination of two markers (CA 19-9 and CEA) provided the greatest sensitivity in Stages A and D tumors (60 percent and 100 percent, respectively); the incidence did not change when measurements of other antigens were associated. For Stages B and C, determination of at least three markers was necessary, the association of CEA, TPA, and CA 19-9 being that which showed the greatest sensitivity, 78 percent and 91 percent, respectively. CONCLUSIONS: It would be advisable to include monoclonal antibody determination of CEA, TPA, and CA 19-9 in the diagnosis of adenocarcinoma, despite the fact that ultimate sensitivity will depend on the degree of tumor extension or on the presence of metastasis.

Adenocarcinoma↗

PubMed1978

Proteolytic release of antigenic fragments corresponding to normal fecal antigen and non-specific cross-reacting antigen from carcinoembryonic antigen.

Three immunogenic parts have so far been identified in the carcinoembryonic antigen (CEA) molecule. These are: determinants cross-reactint with the normal fecal antigen (NFA) (NFA determinant); determinants cross-reacting antigen (NCA) (NCA determinant); and determinants which appear to be more cancer-specific (cancer determinant). The chemical nature of these parts of the CEA molecule was investigated by digestion with proteolytic enzymes together with anti-CEA preparations with which these three immunogenic parts of CEA molecule could be identified. The CEA digest obtained with pepsin did not react in immunodiffusion and radioimmunoassay, indicating that pepsin completely destroyed all the antigenic parts. Digestion by pronase E destroyed only the cancer determinant and liberated two antigenic fragments corresponding to the NFA determinant and the NCA determinant, respectively. These results suggest that the cancer determinant may reside in a protein or a peptide part of the molecule. The chemical nature of the NFA and NCA determinant remains to be clarified.

Antigens↗

PubMed1994

A prospective study of serum tumour markers carcinoembryonic antigen, carbohydrate antigens 50 and 242, tissue polypeptide antigen and tissue polypeptide specific antigen in the diagnosis of pancreatic cancer with special reference to multivariate diagnostic score.

The aim of this study was to assess by a stepwise multivariate discriminant analysis the value of four current serum tumour markers - carcinoembryonic antigen (CEA), carbohydrate antigen (CA) 50 and CA 242 and tissue polypeptide antigen (TPA) - and a new serum tumour marker, tissue polypeptide specific antigen (TPS), in the diagnosis of pancreatic cancer. The serum values were measured in a prospective series of patients with jaundice, with unjaundiced cholestasis and with a suspicion of chronic pancreatitis or a pancreatic tumour (n = 193). There were 24 patients with a cancer of the pancreas and two patients with a cancer of the papilla of Vater in this series. Our results showed that CA 50 (P < 0.001) and TPA (P < 0.01) were the best marker tests in predicting pancreatic malignancy. Also, the TPS (P = 0.07) and CA 242 (P = 0.08) tests showed marginally significant independent discriminating power, while the CEA test did not (P = 0.12). In order to sum up the contributions of different markers, a diagnostic score (DSI) was developed. The discrimination function was: DS1 = CA 50 x 1.75 + TPA x 0.62 + TPS x (-0.37) + CA 242 x (-1.21). The sensitivity of DS1 in detecting pancreatic cancer was 36% with a specificity of 90% and an efficiency of 82%. When the combination of CA 50 and TPA was used as a test, the discrimination function (DS2) was: DS2 = CA 50 x 0.69 + TPA x 0.67. The sensitivity of DS2 was 44% with a 88% specificity and an efficiency of 82%. According to this analysis, the further advantage gained by a computer-aided scoring system seems to be limited, since despite the considerably high specificity and efficiency its sensitivity remained low. In the present analysis the best combination in diagnosing pancreatic cancer was the combination of CA 50 and TPA.

Adult↗

PubMed2001

Murine six-transmembrane epithelial antigen of the prostate, prostate stem cell antigen, and prostate-specific membrane antigen: prostate-specific cell-surface antigens highly expressed in prostate cancer of transgenic adenocarcinoma mouse prostate mice.

To identify genes that are differentially up-regulated in prostate cancer of transgenic adenocarcinoma mouse prostate (TRAMP) mice, we subtracted cDNA isolated from mouse kidney and spleen from cDNA isolated from TRAMP-C1 cells, a prostate tumor cell line derived from a TRAMP mouse. Using this strategy, cDNA clones that were homologous to human six-transmembrane epithelial antigen of the prostate (STEAP) and prostate stem cell antigen (PSCA) were isolated. Mouse STEAP (mSteap) is 80% homologous to human STEAP at both the nucleotide and amino acid levels and contains six potential membrane-spanning regions similar to human STEAP. Mouse PSCA (mPsca) shares 65% homology with human PSCA at the nucleotide and amino acid levels. mRNA expression of mSteap and mPsca is largely prostate-specific and highly detected in primary prostate tumors and metastases of TRAMP mice. Both mSteap and mPsca map to chromosome 5. Another known gene coding for mouse prostate-specific membrane antigen (mPsma) is also highly expressed in both primary and metastatic lesions of TRAMP mice. These results indicate that the TRAMP mouse model can be used to effectively identify genes homologous to human prostate-specific genes, thereby allowing for the investigation of their functional roles in prostate cancer. mSteap, mPsca, and mPsma constitute new tools for preventative and/or therapeutic vaccine construction and immune monitoring in the TRAMP mouse model that may provide insights into the treatment of human prostate cancer.

Adenocarcinoma↗

PubMed1997

The additional value of free prostate specific antigen to the battery of age-dependent prostate-specific antigen, prostate-specific antigen density and velocity.

This study describes the value of using the fraction of free prostate-specific antigen as a further marker in the early detection of prostate cancer. This newly introduced marker is compared to the usual battery of age-dependent total prostate-specific antigen, prostate-specific antigen density (microg/l x g tissue) and prostate-specific antigen velocity (microg/l x year). Determination of total prostate-specific antigen and free prostate-specific antigen was performed on fresh serum samples obtained from 3470 symptomatic patients aged 45-80 attending the Urology Clinics, or their General Practitioners. Among them, 310 patients had total prostate-specific antigen above the age-dependent cut-off, and/or free/total prostate-specific antigen under 11%, with different prostate-specific antigen densities and velocities. Only 147 patients complied to undergo biopsy: in 72 of those patients, benign prostatic disease was histologically confirmed, while in 75 patients primary prostate cancer was histologically confirmed. Total and free prostate-specific antigen levels were determined using the third generation DPCs prostate-specific antigen assay performed on the Immulite automated immunoassay instrument. Total prostate-specific antigen age reference values were adopted from Oesterling et al. (J Am Med Ass 1993; 270:860-4); the prostate-specific antigen density was considered suspicious of prostate cancer if it was greater than 0.15 microg/l prostate-specific antigen per gram tissue (Seaman et al. Urol Clin N Am 1993; 20:653); prostate-specific antigen velocity greater than 0.75 microg/l x year (Carter et al., J Am Med Ass 1992; 267:215) was considered suspicious for prostate cancer. Of the 147 patients, 75 had prostate cancer and 72 had benign prostatic hypertrophy. The difference between prostate cancer and benign prostatic hypertrophy was significantly reflected only by free/total prostate-specific antigen and prostate-specific antigen velocity. These parameters also provided the best sensitivity and specificity. Only these parameters proved to be significant when using a backwards logistic regression model (prostate-specific antigen velocity, p = 0.007 odds ratio 2.782; free/total prostate-specific antigen %, p = 0.016 odds ratio 2.678). Combinations of various parameters became significant when including free/total prostate-specific antigen, increasing prostate cancer detection to 88%. We conclude that free/total prostate-specific antigen is the most significant among prostate-specific antigen quantities (total age-dependent prostate-specific antigen, prostate-specific antigen density and prostate-specific antigen velocity). Adding this parameter to other prostate-specific antigen parameters improves the discrimination between prostate cancer and benign prostatic hypertrophy for the population at risk.

Aged↗

PubMed1985

An induced fit hypothesis for antigen recognition by T lymphocytes: a role for specific antigen retention structures on antigen-presenting cells.

The nature of T lymphocyte recognition of foreign antigens is not known, despite recent advances in elucidating the cellular structures that may be involved in the specific interactions. The central difficulty in this process is that T cells respond to foreign antigen only in the context of major histocompatibility complex (MHC) antigens expressed by another antigen-presenting cell. In addition, T cells that interact with class II MHC antigens do not bind foreign protein antigens in their native form, but seem to recognize only proteolytic peptide fragments as the relevant antigen. The simplest explanation for these observations is that the class II MHC antigens themselves bind antigenic peptides to form the appropriate determinant that interacts with the antigen-specific T cell receptor. However, to date no such antigenic complex has been found with MHC antigens despite rigorous attempts at their demonstration. One alternative explanation described here is that there is no preexisting foreign antigen-MHC antigen complex prior to interaction with T cells, and it is the T cells that cause the two moieties to become associated for recognition by a single antigen-specific T cell receptor. Central to this mechanism is that foreign antigenic peptides must be associated with specific antigen retention structures (SARS) expressed by antigen-presenting cells which retain and protect the peptide on the cell surface. These SARS, upon interaction with T cell membrane moieties, would subsequently associate with MHC antigens. A hypothesis to describe this mechanism is developed to account for published observations of antigen processing by antigen-presenting cells and T cell antigen recognition, and makes several predictions that are experimentally testable. This mechanism is also generally applicable to other cellular interactions in which soluble peptide mediators may become associated with surface components of one cell type, and this newly formed complex is in turn recognized by a receptor on a second cell type to deliver functional signals.

Animals↗

PubMed1980

Prevalence of Williams e1 antigen in comparison with e2 antigen in hepatitis B antigen carriers and patients in hemodialysis unit.

The prevalence of both e1 and e2 antigens in 1,158 sera of asymptomatic HBsAg carriers, carriers in hemodialysis units, and HBsAg-negative blood donors was examined. The detection rate of e1 antigen was as high as 80% in asymptomatic carriers, 95% in hemodialysis patients, and even 13.1% in HBsAg-negative donors. All of the e1 antigen-positive specimens in such HBsAg-negative sera were found to have both or either anti-HBs and anti-HBc, suggesting the past history of Hepatitis B virus (HBV) infection of the donors. In the HBsAg-positive serum, the detection rate of e2 antigen (17%) was lower than that of e1 (80%), and all sera having e2 antigen were positive for e1 antigen. The titers of HBsAg, HBcAg, and anti-HBc in e2 antigen-positive sera were higher than that of sera detecting only e1 antigen. The appearance of e1 antigen and e2 antigen in the course of post-transfusion hepatitis B was studied with five cases. Retrospective study showed that three of them each received one unit of HBsAg-positive blood, and the other two received HBsAg-negative blood but with high-titered anti-HBc. In four cases out of five, in which e2 antigen was detected during the course of infection, the initial detection of e2 antigen occurred at or just before the elevation of liver enzyme levels. On the other hand, e1 antigen was detected relatively early after transfusion, and the time of onset. Moreover, the detection period of e1 antigen persisted longer, even after the disappearance of HBsAg antigenemia. These two separate studies suggest that not only e2 antigen but also e1 antigen are associated with the infection of HBV, but they are distinct from each other; the e2 antigen may have the properties of a signal of the viral activity in the patient as suggested by many others, but e1 antigen does not seem to bear such diagnostic values.

Adult↗

PubMed1975

Immunogenic properties of modified antigen E. II. Ability of urea-denatured antigen and alpha-polypeptide chain to prime T cells specific for antigen E.

Ragweed antigen E loses its major antigenic determinant after denaturation in 8 M urea. The urea-denatured (UD) antigen and alpha-polypeptide chain isolated from the denatured molecule possess their own antigenic determinant(s) but lack the major determinant of the native molecule. The UD antigen and alpha-chain, however, are capable of priming mouse T cells specific for antigen E. Priming of A/J mice with the modified antigen enhanced both IgG and IgE antibody responses to antigen E. Both UD antigen-primed spleen cells and alpha-chain-primed spleen cells collaborate with DNP-primed cells to give an adoptive secondary anti-DNP antibody response to DNP-ragweed antigen in syngeneic irradiated mice. Pretreatment of A/J mice with an i.v. injection of alpha-chain partially suppressed both IgE and IgG antibody responses to antigen E. Weekly injections of alpha-chain or UD antigen to antigen E-primed animals depressed on-going IgE antibody response, and suppressed secondary IgE antibody response to antigen E. Transfer of spleen cells from animals treated with the modified antigen to irradiated recipients followed by challenge with native antigen showed that the adoptive secondary response was suppressed by injections of modified antigen to the donors. The results indicate that the immunocompetent cell population was changed by the treatment and provide an experimental model to analyze the immunologic effect of hyposensitization treatment.

Allergens↗

PubMed1984

The MT3 specificity resides on a novel human class II antigen distinct from the HLA-DR antigen and DC-like antigen.

The MT3 specificity is closely associated with the HLA-DR4, DR7, and DRw9, and is a supertypic specificity. To determine whether the MT3 specificity resides on a novel class II antigen, the MT3 antigen, DR antigen and the DC-like antigen from the DR4-, DR7- and DRw9-homozygous B lymphoid cell lines were identified and compared with one another by two-dimensional gel electrophoresis using alloantisera. The analysis revealed that each of the three antigens exists as a structurally distinct class II antigen in each cell line. The light chains of the MT3, DR and DC-like antigens are different in charge from one another. The molecular weight of the heavy chains of the MT3 and DR antigens is higher than that of the DC-like antigen. On the other hand, no electrophoretic differences are observed between the heavy chains of the MT3 and DR antigens. These results strongly suggest that the MT3 specificity resides on a light chain of a novel class II antigen distinct from the DR antigen and the DC-like antigen. These observations also support our previous proposition that the MT3 antigen belongs to the fourth group of the human class II antigens.

B-Lymphocytes↗

PubMed1981

Antigen handling in antigen-induced joint inflammation: kinetics of a second intra-articularly injected dose of antigen in an already established antigen-induced joint inflammation.

The fate of a second intra-articularly (i.a.) injected dose of bovine serum albumin (BSA) in an already established BSA-induced knee-joint inflammation was compared with that of a paired first arthritis-inducing injection of the same dose of BSA into the contralateral knee of immunized rabbits. External counting of i.a. radiolabelled BSA indicated more rapid initial elimination but approximately two-fold increase in long-term retention of BSA after a second i.a. injection as compared with a first one. Direct counting of dissected joint structures confirmed these data and localized the retained BSA predominantly in hyaline articular cartilage, menisci and ligaments, both after a first and after a second injection. Since the protocol used in these studies per se excluded systemic factors as possible determinants of the difference in antigen retention observed, local alterations in the already inflamed joint caused this difference. Control studies indicated that both humoral immune factors and non-specific inflammatory changes within the chronically inflamed joint determine the phenomenon. Local alterations in an immune-induced chronically-inflamed joint increase its antigen-binding capacity, a mechanism of possible relevance to the chronic course and the occurrence of exacerbations characteristic of some forms of human arthritis.

Animals↗

PubMed1975

Immunogenic properties of modified antigen E. III. Effect of repeated injections of modified antigen on immunocompetent cells specific for native antigen.

It has been shown that ragweed antigen E loses its major antigenic determinants after denaturation in 8 M urea, but urea-denatured (UD) antigen and an alpha-polypeptide chain isolated from the denatured molecules are capable of priming mouse T cells specific for native antigen. Weekly injections of 10mug UD antigen or alpha-chain into antigen E-primed animals depressed the ongoing IgE antibody response, whereas injections of the same dose of antigen E failed to depress the antibody response. It was found by adoptive transfer experiments that helper activity of antigen E-primed splenic T cells was depressed by the treatment of the donors with either modified antigen or native antigen E. The same treatment of antigen E-primed animals depressed the DNA synthetic response of their splenic T cells to antigen E. The treatment of antigen E-primed animals with UD antigen resulted in a decrease of antigen E-specific IgE-B cells and IgG-B cells in their spleen, whereas the treatment with native antigen expanded the B cell populations. In view of the results obtained in the mouse, cellular basis for the immunologic effects of hyposensitization treatment is discussed.

Animals↗

PubMed1982

Host antigens on avian oncoviruses: presence on viruses produced by quail, duck and rat cells of antigens related to membrane antigens of chick embryo fibroblasts and chicken erythrocytes.

Avian sarcoma viruses (ASV) produced by Japanese quail embryo fibroblasts (QEF) were inactivated to the same degree as ASV produced by chick embryo fibroblasts (CEF), with or without complement, by rabbit antisera to CEF and to membrane antigens of chick embryo and adult chicken erythrocytes, in particular their unique age-specific antigens. ASV produced by duck embryo fibroblasts (DEF) were only inactivated by the antisera to the chicken erythrocyte antigens. Hence, viruses produced by QEF and DEF bear on their envelope antigens related to the chicken antigens picked up by ASV in CEF. These antigens are presumably coded by the quail and duck cells, since antigens related to the chicken antigens were found on QEF and on quail and duck erythrocytes. Antigens related to the chicken antigens have also been found on ASV shed in low amounts by semi-permissive rat sarcoma cells (line 17RBI77) and on the surface of these cells, as well as on that of another semi-permissive cell line (RBH) originating from a hamster sarcoma produced by inoculation of the rat cells. The origin of these antigens, which may play a role in semi-permissiveness, remains to be explained since they do not appear to be normally expressed by rat or hamster cells. It was also found that, contrary to an earlier conclusion and in agreement with a recent report, uninfected CEF bear on their membrane an antigen that is related or identical to the specific antigen of chick embryo erythrocytes. Therefore, only the antigen related to the adult-specific chicken erythrocyte antigen does not pre-exist on CEF.

Animals↗